North Korea’s Nuclear Intentions, Out There for All to See

FOR much of the nuclear age, nations that sought the ultimate weapon kept their intentions and test sites veiled in secrecy, hidden from public view and foreign governments. The first detonations by the United States and the Soviet Union were top secrets and India’s test in 1998 caught American intelligence agencies by surprise.

No more, or so it seems. North Korea all but yelled “look at me” in announcing that it plans to conduct its first nuclear test, which experts say might come at any time or perhaps never. “Shouting from the rooftops is new,” said Robert S. Norris, author of “Racing for the Bomb” (Steerforth Press, 2002). “It’s an unusual way to go about asserting your status as a member of the nuclear club.”

What lies behind this outbreak of atomic exhibitionism? While deciphering the intentions of one of the world’s most cryptic regimes seems next to impossible, analysts say likely factors include North Korea’s taste for bold propaganda as well as its awareness that new classes of satellite technology are making it increasingly hard to hide nuclear sites anyway.

In the bad old days of the cold war, nations that aspired to nuclear fearsomeness wrestled with a fundamental conflict. While seeking to project a terrifying image, they also wanted to keep many test details secret so adversaries would face greater difficulty in crafting potential countermeasures and knowing the exact dimensions of the threat.

“If it was a dud, you didn’t want to announce that it was a dud,” recalled Philip E. Coyle III, a former head of weapons testing at the Pentagon and former director of nuclear testing for the Lawrence Livermore National Laboratory, a weapon design center in California.

Nuclear powers hid vast industrial complexes in the middle of nowhere and often tried to keep their tests secret. In 1949, it took weeks for Washington to find out that Moscow had detonated a bomb that ended the American atomic monopoly.

The United States responded with a costly array of instruments meant to pull back the veil — everything from high-flying planes that could sniff out whiffs of stray radioactivity to giant microphones that listened for the distant nuclear rumbles. Jeffrey T. Richelson, who profiles the era in “Spying on the Bomb” (Norton, 2006), said the gargantuan effort cost billions.

Today, a new factor is opening the secretive art to the public: a generation of commercial satellites that can peer down from the heavens to see objects on the ground as small as two or three feet wide, enough to distinguish between a car and a truck. The orbiting eyes can ogle hot tubs and backyard trampolines as well as troop movements and dictators’ lairs, undermining what was once a government monopoly on such reconnaissance.

Last week, CNN broadcast satellite images of what it called a potential test site located in a valley in North Korea not far from its northeastern coast. Pentagon sources, CNN reported, confirmed suspicious movements there of people, equipment and vehicles that tended to buttress North Korea’s claim that it could detonate a bomb.

GeoEye, a provider of commercial satellite pictures based in Dulles, Va., made available to The New York Times images of the same military complex, but focusing on a rocky site farther up the rugged valley. On July 31, the company’s satellite looked down from a height of nearly 300 miles, its camera and telescope zooming in on what appears to be a tunnel entrance dug into the flank of a high mountain and, nearby, buildings that could store mining equipment.

“We provide customers with a map-accurate view of the ground they can’t get any other way,” said Mark E. Brender, a company spokesman. “Eyes in the sky are good for governments in the region who are concerned about this, and good for customers who need to know as much as they can about what may be going on in North Korea.”

American officials say government spy satellites monitor about a half-dozen suspicious sites in North Korea but have also focused on the military base.

The much-scrutinized base would be an ideal spot for North Korea to set off an underground nuclear blast if it wanted to make a splash. A senior American intelligence official, who spoke on the condition of anonymity because of federal secrecy rules, noted that the mountainous redoubt “is a place they know we’re looking at.”

Along with lots of civilians. Google Earth, on the Web at earth.google.com, features some of the best public snooping on the isolated base, its software combining close-up images and altitude data so the surrounding mountains rise up in three dimensions. A viewer can zoom overhead like a spy plane. The images come from DigitalGlobe, a satellite company in Longmont, Colo.

Google views of the tunneling area, near 41.279 degrees north latitude and 129.087 east longitude, show a set of industrial buildings and what appears to be a mine entrance.

For North Korea, the emergence of the commercial spies would seem to cut two ways, either reinforcing its propaganda effort or threatening to undermine it by exposing a ruse.

And paradoxically, the best monitor of its actions, the world’s largest and most sensitive network meant to detect nuclear blasts, run out of Vienna by the United Nations, is powerless to judge the North’s real intentions until there is a test. This network, with its global arrays of hundreds of sensors, is meant to police a shaky global ban on the explosive tests, mainly by listening for the faint reverberations of shock waves.

If North Korea decides to go ahead and press the button, this network will help discern exactly what North Korea has succeeded in developing by way of nuclear arms — or not.

“Until they do, people can argue about their capability,” said Dr. Coyle, the weapons expert. “But once they test, there’s no question. The world will know.”

A version of this article appears in print on , on Page WK5 of the New York edition with the headline: North Korea’s Nuclear Intentions, Out There for All to See. Order Reprints|Today's Paper|Subscribe